Hide server IP on sendmail?

Question

Email

In general, the point is that I do not want to show the server's IP. I put it on cloudflare, and everything is cool, only when sending letters, the server ip lights up.
I tried through mailgun, but it's just a failure - sometimes letters go for 1-3 minutes, and even 5-10. (Through the sendmail default, they come with lightning speed).

Answer 1

No, it is not possible to hide the server ip. This is one of the main components in the fight against spam.
Do not want to shine the address of the main server? Take a small separate server, put sendmail on it, build on your API, send as much as you like (if it's not spam, of course).

Answer 2

He not only indicates it in a letter, but also informs the recipient. You can hide the IP :) To do this, you just need to write your own analogue of SMTP and achieve its adoption as a standard :) And there is no other way :)